Air-feed brake for rock drills



Sept. 22, 1925. 1554,766

F. M. SLATER AIR FEED BRAKE FOR ROCK DRILLS Filed Oct. 12, 1922 2 Sheets-Sheet l 1 Eco? 5/02?!" Sept. 22, 1925.

F'. M. SLATER AIR FEED BRAKE FOR ROCK DRILLS Filed Oct. 12. 1922 2 Sheets-Sheet 2 INVENTOR fluufMJlflfa ATTOR EY Patented Sept. 22,1925.

UNITED STATES PA a FRED M. SLATER, or nAsronrnNnsYLvANm, Assrenonro INGERSQLL-RAND-COM- IPANY, or JERSEY CITY, nnw messy," A CORPO-RATIGN or nnwcnnsnv;

AIR-rent) BRAKE non noox .DRILLs.

Application filed October 112, 19,22. -.Serial No. 593$).

To all whom it may concern:

Be it known that I, FRED M. Sm run, a citizen of the United States, and a resident of Easton, county of Northampton, and State of Pennsylvania, have invented a certain Air-Feed Brake for Rock Drills, of

which the following is a specification, ac-

companied by drawings.

This invention relates to fluid actuated rock drills, but more particularly to a device for controllingthe feeding element of a stope drill, although the invention may be applied to any drill having a fluid actuated feeding element.

The invention is illustrated in connection with a stope drill having independent rotationfor thedrill steel shown in this instance as a rotary motor, and the objects of the invention are to enable the members of the fluid actuated feeding ,element of a machine of this type, to. be positively locked against relative movement or to have the relative movement checked without positively looking the members.

Another object of the invention is to effect the control of the braking device by fluid actuated means operating in accordance with the resistance to rotation encountered by the drill steel in operation.

The invention is illustrated in the aocompanying drawings, in which- Figure l is a longitudinal sectional elevation of ,a stope drill embodying the invention,

Figure 2 is a transverse sectional view of Figure 1 on the line 22 lookingin the direction of the arrows,

Figure 3 is a transversesectional view of Figure l on the line 33 looking in the direction of the arrows,

Figure .4; is a transverse sectional view of Figure 1 on the line 4& looking in the direction of the arrows,

Figure 5 is a side elevation partly in longitudinal section of a stope drill embodying a modification of the invention, and

Figure 6 is a transverse sectional view through the motor of Figure .5 on the line (r-=6 looking in the direction of the arrows.

Referring to the drawings, the cylinder A of the rock drill is provided with a reciprocating pistonB adapted to impart blows of impact to the anvil block C through which they are transmitted to the shank of the drill steel'D. The drill steel extends into the chuck 'E in the frontghead F, which chuck is adapted :to bexrotated through suitable gearsG and Hand shaft J from anine dependent rotation motor, in this instance, shown as a rotary gear motor comprising the gears K and L in the back cylinder e};- tension 0.

Motive fluid is admitted to the motor casing through the inlet P and exhausted at the outlet Q in the usual manner for driving the gear motor and imparting rotation to the drill steel 1).

The fluid pressure feeding element COIIl prises two relatively movable members and includes the feed cylinder P- and the feed piston Q, having the piston rod It provided with the. rock engaging pointer S. The pis ton rod It non-rotatably; engages the cylim der P and is provided with a groove T sengaging the tongueor rib U. on the-cylinder. The feed cylinder P. is provided with a feed cylinder head V over which is placed the head block W, and the back head X of the machine is interposed between the backcylinder extension 0. and the head block The parts are adapted to belsuitably held together by the usual side bolts Y, a portion of one of which is shown in Figurea,

The braking device includes a longitudi nally movable and rotatable brake rod Z.

ha g' e ds a eng ging a re d slee e 12 within the piston Q, which sleeve in this instance serves to hold the piston to the piston rod R, as by ,means of the threads 0. Interposed between the head d of the. brake rod Z and the feed cylinder head V are-two sets of longitudinally movable brake discs, one set of discs .6 being keyed to the feed cylinder head as by means of the keys or ribs f, and the other setof discs-g alternating with the discs 6 and being keyed to the brake rod Z as by means-ofthe keys orribs lay on the brake rod. The head block W is suitably provided with a partition y forming'a pressure chamber in the head block and a flexible diaphragm'o preferably located in, the said pressure chamber over a button or plunger p extendingthrough the partition j and bearing on the head (Z of the brake rod Z, so that pressure fluid supplied to the pressure chamber is will force the diaphragm o and plunger p downwardly upon the brake rod Z, which forces the brake discs 6 and 9 together, thus locking the brake rod Z against rotation or checking its rotation according to the pressure applied. Pressure fluid is supplied to the machine through the throttle valve 9 in the back head X controlled by the usual handle 1" and a passage 8 leads from the throttle valve through the back head X and head block W and feed cylinder head V for supplying pressure fluid to the feed cylinder When the brake discs are released, the feed cylinder may rise on the feed piston Q atthe same time carrying the brake rod Z upwardly' and'causing thefbrake rod to rotate. When the brake .rod against rotation or if its rotation is retarded, thefeeding element is locked or checked in itsmovement. 7

In Figures 1 to 4 inclusive,rone form of device is illustrated forautomatically controlling the supply of pressure fluid to the pressure chamber 72 above the diaphragm 0 automatically in accordance with the'resistance to rotation of the drill steel. In said figures, the back-head X is provided with a handle 2? pivoted for transverse movement upon a pivotpin a. Thestop ulimits the movement of the.handle inone direction,

and aprojection won thehandleis adaptedv to bear upon the end of the valve'g located inthe backhead'X and controlling the passages 2 a'nd3 in the .back'head leading from thethrottle Valve 9 to the pressure chamber 10 above the diaphragm o A passage 70 in the back head X forms a communication be:

tween thechamber 70 and the atmosphere when the valve .y is in its inner position. A spring lcv'int'erposed between the valve y and the plug 5 normally holds the valve in the position indicated in Figures land 2, in which thesupply offluid to the chamberlc is cut ofl. Upon suflicient increase of resistance to rotation encountered by the drill steel, the machine will tendto twist or turn backwardly and assuming that the operator has his hand upon thehandle t,

holding said handle against rotation, itwill a which will admit pressure fluid to the cham ber l0, depressing the diaphragm 0 and toreing the head 6 of thebrakejrod Z downwardly'upon the;brake discs, thus carrying the discs into engagement and either locking the brake rod Z against rotation or checking its rotation to apply a braking efl'ectto the feeding element. Upon decrease of resistanceto rotation, the spring 4t will return the valve to normal position cutting off the supply of pressure fluid to'the chamber is, and pressure fluid from the chamber is will 'be exhausted to atmosphere through the passage V In Figures 5 and 6 a modification of the is locked valve. trols the passages 13 and 14 leading from invention is shown, in which supply of pressure fluid to the chamber is above the diaphragm 0 is automatically controlled by a valve 6 located in the back head 7 and adapted to be actuated by increase of back pressure in the rotation motor, due to increased resistance to rotation encountered by the drill steel D. In this instance, motive fluid is supplied from the throttle valve 9 through the passage 8 to the inlet P of the motor and a branch passage 9 leadsfrom the inlet of the motor to the valve chamber 10 in front of the enlarged head 11 of the A smaller head 12 of the valve conthe throttle valve 9 to the pressure chamber k. The outer face of the smaller valve head 12 is vented to atmosphere through the port 15. The head block W is provided with a rotation handle '16 of the usual form, rigidly connected thereto upon which the operator maintains his hand during the operation. Upon a suflicient increase of resistance to rotation of the drill steel D, the back pressure in the motor casing will increase andwill force the valve inwardly, since the pressure on the enlarged head 11 will overcome'the differential pressure between the heads 11 and 12 and'communication will be established between the passages 13 and 14 so that the diaphargm awill be forced downwardly and the braking effect will be. applied to the brake rod Z as de: scribed in connection with Figure 1, it being understood that the construction of the brake and the feed cylinder and its partsis the same in Figure 5 as in Figure 1. Upon decrease of back pressure in the gear motor, the differential pressure between the valve heads 11 and 12 will'move the valve to normal position and cut off the supply of fluid pressure to the chamber la, and pressure fluid in the chamber 7c will be exhausted to at mosphere past the smaller head 12 and through the port 15.

I claim:

1. In a fluid actuated rock'drill having independent rotation for the drill steel, the combination of a percussive element, a fluid actuated feeding cylinder, a piston slidable insaid feeding cylinder and secured against rotation with'respect thereto, a back head for the percussive element, a handle pivoted on the back head for resisting rotation of the rock drill, a fluid actuated brake associated with said piston for checkingand preventing relative movement between the piston and the feeding cylinder, and aanormally closed valve in said back head in constant contact with the handle for controlling the action of the said brake whereby the valve is opened by the handle for admitting pressure fluid to the brake,

2, In a fluid actuated rock drill having independent rotation for the drill steel, the

combination of a percussive element, a fluid actuated feeding cylinder, a piston slidable in said feeding cylinder and secured against rotation with respect thereto, a rockengaging foot piece carried by the piston, a back head for the percussive element, a handle mounted pivotally on said back head for resisting rotation of the rock drill when the steel binds in the drill hole, a rotatable brake rod movable with the feeding cylinder and having threaded engagement with said piston whereby said rod is rotated, a fluid actuated brake for controlling rotation of said rod, a valve in said back head in constant contact with the handle whereby the valve is automatically opened to admit pressure fluid to the brake when the rock drill rotates against resistance applied to the handle, and a spring to hold the valve against the handle.

3. In a fluid actuated rock drill having independent rotation for the drill steel, the combination of a percussive element, a fluid actuated feeding cylinder, a piston slidable in said feeding cylinder and secured against steel binds in the drill hole, a rotatable brake rod movable with the feeding cylinder and having threaded engagement with said piston whereby said rod is rotated, a fluid actuated brake associated with said rod for checking and preventing rotation thereof, a diaphragm between said brake and the back head forming a pressure chamber, a valve in said back head in constant contact with the handle whereby the valve is automatically opened to admit pressure fluid to the pressure chamber for applying the brake when the rock drill rotates against resistance applied to the handle, and a spring for holding the valve in a normally closed position. In test mony whereof I have signed this specification.

FRED M. SLATER. 

